The present device, as well as the associated method, above all relate to intraluminal imaging for medical applications, but can be used in other technical areas in which tomographic imaging data is to be obtained from a cavity or a hollow body. For this type of intraluminal imaging an imaging catheter or an imaging endoscope for recording intraluminal sectional images is introduced into the corresponding lumen. Thus for example, U.S. Pat. No. 6,134,003 A shows this type of imaging catheter, which creates the sectional images with the aid of optical coherence tomography (OCT). In medical applications layers of tissue can be recorded up to a specific depth of penetration of the radiation used with an imaging catheter of this type.
The processing of pulling the imaging catheter out of the lumen at a defined speed is known for the creation of sets of 3D images or of 3D images of the relevant hollow organ or cavity. This obtains a number of sectional images, from which, because of the known speed, a 3D image data set can be reconstructed.
For the three-dimensional reconstruction of cavities with a curved or wounded course from such a stack of two-dimensional sectional images however there is the problem of the individual sectional images not being able to be assembled in the correct spatial orientation to the three-dimensional image data set. The primary reason for this is that the exact position and orientation of the catheter tip and thereby the position of the image plane of each individual sectional image when the flexible catheter is used in curved or wounded cavities cannot be determined from the data obtained during imaging. The same problem occurs for principally similar problem definitions, such as for example the use of intraluminal ultrasound, confocal microscopy and/or the use of endoscopes instead of catheters.
The creation of a 3D image data record of a curved or wounded cavity or hollow organ has a role to play for example in the manufacturing of an insert, of an in-the-ear hearing aid for example, for the lumen of the auditory canal of a patient. To encompass the geometry of the inner ear a mold has previously been created which—after hardening and processing—is translated with a 3D scanner into a three-dimensional data set. However the production of such a mold is very uncomfortable for the patient. The entire process up to the point at which the three-dimensional data record is obtained, which is then used as the basis for creating the patient-individual insert, is a very complex one. There is therefore a need for a device and a method with which such a 3D image data record can be created in a simple manner.
A method is known from U.S. Pat. No. 5,830,145 A for reconstruction of 3D image data sets from intraluminal sectional images, which were recorded with an intraluminal ultrasound catheter (ILUS catheter). In this method special catheters are used which feature sensors on their tips. These enable the three-dimensional position and orientation of the catheter tip to be recorded at any time during the movement of the imaging catheter with a pullback unit. A three-dimensional track to which the individual sectional images are assigned is obtained from the 3D-position data. In this way a correct reconstruction of the 3D image data set can be obtained from the 2D sectional images. The execution of this intraluminal imaging however requires catheters with special position sensors as well as a corresponding tracking system.
A device for intraluminal imaging is known from U.S. Pat. No. 4,819,620, which comprises a rigid guide pipe made of a material which is transparent to the radiation used for imaging. The guide pipe has an internal diameter adapted to accommodate and guide an imaging instrument and at least one marking recognizable with imaging at a known position on the guide pipe.